A simple diagnostic method for the differentiation of Tamm-Horsfall glycoproteins from healthy probands and those from recurrent calcium oxalate renal stone formers

Tamm-Horsfall glycoproteins (THPs)^* from healthy probands, and those from a majority of recurrent calcium oxalate renal stone formers, reveal different properties when analyzed using isoelectric focusing. The pl-values of THPs from healthy probands are approximately 3.5 while THPs from recurrent renal stone formers have pl-values between 4.5 and 6. The two groups of THPs exhibit completely different protein patterns in IEF. This proves the structural difference of these THPs. The differences in IEF analysis allow the differentiation between THPs from healthy probands and those from recurrent calcium oxalate stone formers. These differences could possibly by used as a simple diagnostic method for the recognition of recurrent calcium oxalate renal stone formers.     

Effect of the calmodulin inhibitor R24571 (calmidazolium) on rat embryos cultured in vitro

Summary The possible effects of inhibition of the calcium-binding protein, calmodulin, on mammalian morphogenesis have been investigated by culturing rat embryos in vitro from 9 1/2 to 11 1/2 days of development in the presence of R24571 (calmidazolium), a specific inhibitor of calmoldulin. Embryos cultured in 10^–2 mM R24571 for 48 h show inhibited development and exhibit a range of morphogenetic abnormalities including assymetry and neural tube defects. Embryos exposed to R24571 for the first 24 h of a 48 h culture are more severely affected than embryos exposed to R24571 for the last 24 h.Acknowledgments. We wish to thank Mr C. Veltkamp and Mr B. lewis for their expert help with the scanning electron microscopy and photography.     

Increased mitochondrial palmitoylcarnitine/carnitine countertransport by flavone causes oxidative stress and apoptosis in colon cancer cells

Cancer cell metabolism is characterized by limited oxidative phosphorylation in order to minimize oxidative stress. We have previously shown that the flavonoid flavone in HT-29 colon cancer cells increases the uptake of pyruvate or lactate into mitochondria, which is followed by an increase in O₂^−.. production that finally leads to apoptosis. Similarly, a supply of palmitoylcarnitine in combination with carnitine induces apoptosis in HT-29 cells by increasing the mitochondrial respiration rate. Here we show that flavone-induced apoptosis is increased more than twofold in the presence of palmitoylcarnitine due to increased mitochondrial fatty acid transport and the subsequent metabolic generation of O₂^−. in mitochondria is the initiating factor for the execution of apoptosis. Received 12 August 2005; received after revision 12 October 2005; accepted 14 October 2005     

Effects of pCai and pHi on cell-to-cell coupling

Summary Internal longitudinal resistance (r_i), a determinant of cardiac conduction, is affected by changes in intracellular calcium and protons. However, the role and mechanism by which H⁺ and Ca²⁺ may modulate r_i is uncertain. Cable analysis was performed in cardiac Purkinje fibers to measure r_i during various interventions. In some experiments, intracellular pH (pH_i) was recorded simultaneously to study the pH_i-r_i relation. Both intracellular Ca²⁺ and H⁺ independently modified r_i. However, internal resistance of cardiac fibers was insensitive to pH_i changes compared to other tissues. A latent period preceded the pH_i-related changes in r_i and the amount of change depended upon methodology. The results suggest that direct action of protons on r_i may be subordinate to other regulatory processes. Ionic regulation of internal longitudinal resistance may occur by more than one mechanism: i) direct cationic binding to sites on junctional membrane proteins; and ii) H⁺- or Ca²⁺-dependent phosphorylation of junctional proteins.     

论碳素原料对电石生产的影响

阐述了碳素原料的粒度、水分、灰分、挥发分对电石生产的影响,并对某电石厂使用的府谷蓝炭进行了分析。     

水／乙二醇混合溶剂中微波辅助合成碳酸钙

在水/乙二醇混合溶剂中,通过微波辅助加热的方法,研究溶液过饱和度对碳酸钙成核生长的影响。分别采用扫描电子显微镜(SEM)、X-射线粉末衍射(XRD)对所得的样品进行了表征。结果表明,过饱和度的改变对碳酸钙形貌和晶型具有非常明显的影响,分别获得了菱面体状方解石、纤维捆扎状文石、松树枝状球霰石为主体的碳酸钙晶体。     

吸湿相变材料在建筑围护结构中的应用

吸湿相变材料在建筑围护结构中的应用是近年来世界各国研究中的新热点,其开发应用对节约能源,可再生能源的利用,维持生态环境的可持续发展有极其重要的意义。介绍了氯化钙作为吸湿相变材料在建筑围护结构中的应用,有利于节约能源、改善建筑物室内热环境、提高室内舒适度。     

CaCl2的水解反应对固态SiO2显微特征的影响

利用扫描电镜(SEM)和能谱仪(EDS)等手段,并结合热力学理论计算,研究了浸泡在1173 K温度下脱水不完全的CaCl2熔盐中的固态SiO2圆柱样显微特征变化及其原因,初步分析了CaCl2盐的水解反应对固态SiO2电解特性的影响.结果表明,未严格脱水操作的CaCl2盐很容易高温水解,生成的CaO在熔体中的活度只要不低于0.001,即可与SiO2逐级形成CaO·SiO2(CS)、3CaO·2SiO2(C3 S2)和2CaO·SiO2(C2 S)等多种硅酸盐,导致圆柱体外表面的形貌、结构发生较大变化;圆柱体内部渗透进入的熔盐中CaO含量低,形貌变化较小.外表面硅酸盐层的存在使仅内置阴极集流体的固态Si O 2圆柱体电解还原速度减慢和难度增加.     

用醋酸浸泡鸡蛋壳制取活性钙冲剂的研究

目的：寻找成本低廉、来源丰富、服用方便、安全无毒、营养效果好的钙制剂。方法：用15％醋酸浸泡鸡蛋壳,获得有机醋酸钙,加以赋形剂制成钙冲剂。结果1、所得醋酸钙粉末纯度为86．29％．产率为75．11％。2、活性钙冲剂是钙含量为2％的白色、均匀、速溶的干燥颗粒状物。结论：用成本低廉、来源丰富的鸡蛋壳作原料制取活性钙冲剂是可行的。